1. Field of the Invention
The present invention relates to the care, feeding, and experimentation with laboratory animals such as rats, rabbits and the like. More specifically, the field of invention is directed to laminar flow filters which provide a very high efficiency of removal of particular matter of the ambient air and pass the same through animal cages, the latter being positioned in cage racks. The purpose is to provide air for the animals as pure as possible, so that they will not be exposed to micro-organisms which might produce a disease or affect the results of experiments. It is also to minimize the cross-contamination of germs from one animal to another.
2. Description of the Prior Art
The prior art is best described as contained in composite units having a filter, plenum, and blower to which a rack is permanently secured, with the air passing over the rack. The entire prior art unit is mobile, and placed upon casters or other means for moving the same.
The prior art units suffer from numerous disadvantages, not the least of which is precluding the animal rack from being moved to a separate cage washer or other place for cleaning, separate and independent of the filters which would be damaged by such cleaning. Furthermore, because the racks are secured to the filter system, there is a limitation in size of the prior art unit that can be passed through a standard door. In addition, units utilizing HEPA (High Efficiency Particulate Air) filters should not be moved about, since the seal around the filter and its host unit may be broken, and even small air holes can significantly disturb the overall filtration effect. Exemplary of the prior art is a unit known as the Carworth unit sold under the Trademark "STAY-Clean", previously a division of Becton, Dickinson & Company, of New York City, N.Y., the same being currently marketed by Lab Products, Inc. of Garfield, N.J. A further disadvantage of the prior art laminar flow cage racks is the reduced capacity in a given room to handle large numbers of animal cages, and a further reduced filter area.